This invention pertains generally to animal data acquisition systems and particularly to a means for reliable and selective release of animal data acquisition devices.
Animal field studies have become increasingly important as a means for collecting data useful for animal research projects. Data such as physiological condition, migratory habits and range can only be obtained from dedicated field studies of an animal population and/or by tracking the animal population being studied by electronic means such as attaching a data acquisition device to an animal(s). The data acquisition device can include telemetering capability for periodically electronically transmitting data collected by the data acquisition device to a data collection station. It is generally desirable to recover the animal data acquisition device either to recover data stored in the device or, in those instances where data has been previously electronically transmitted, because the data acquisition device itself is expensive. In the case of land animals, recovery of animal data acquisition devices generally requires that the animal wearing the device be physically located and immobilized in some fashion and the data acquisition device removed. Locating and immobilizing the animal can be time consuming and deleterious to the health of the animal. Recognizing this problem, Chapman et al. in U.S. Pat. No. 4,762,088 propose the use of a pyrotechnic release mechanism, actuated by an electrical signal from a remote telemetry actuator such as a radio transmitter, to cause a collar or harness containing a data acquisition device to be released. However, because there is no way to differentiate between various collars, one signal from the radio transmitter can serve to activate simultaneously all the collars which receive the signal. There is presently no way to prevent animal data acquisition devices from being released simultaneously if two animals wearing these collars are in proximity to one another. Further, pyrotechnic devices can be expensive and, in some cases, undesirable for use.
In the case of sea animals, whales, sea lions, seals, etc., a corrodible link can be used to fasten the data acquisition device to the animal. In principle, it is possible by knowing the physical characteristics (i.e., dimensions, composition, etc.) of the corrodible link to calculate the time required for the link to disintegrate, thereby releasing the associated data acquisition device. However, the time required for the link to corrode away is difficult to predict precisely. Consequently, whenever corrodible link technology is used to fasten data acquisition devices to sea animals it is uaually necessary to maintain a recovery crew in the area where the animal is generally located to recover the expensive animal data acquisition device when it is released. This can be a very expensive procedure both in terms of the cost of maintaining a boat and crew at sea as well as lost time. If the animal should leave its normal habitat or weather conditions require the recovery crew to leave the area the data acquisition system can be lost. Thus there is no reliable and accurate way to release a data acquisition device from a sea animal. Moreover, there is presently no way to release animal data acquisition devices from sea animals that are beneath the surface of the water. What is needed is a means for reliably, releasing animal data acquisition devices on command for recovery at a desired time, particularly data acquisition devices useful for sea animals, whether the sea animal is located on the surface or beneath the surface of the water. Further that such means be capable of distinguishing between different data acquisition devices even if the animals wearing the devices are in proximity to one another.
Responsive to these needs, the present invention discloses a novel, inexpensive, miniaturized, programmable remote control apparatus for reliably and selectively releasing an animal data acquisition device. Further, the release device can be either pyrotechnic or a less expensive mechanical device.